Facile One Step Rapid Laser Reactive Processing of Protonic Ceramic Electrochemical Cells

Abstract

Greenhouse gas emissions are becoming more and more serious issue with fossil fuels combustion. Renewable energy sources are the key to solve this problem. Protonic ceramic electrochemical cell (PCEC) is a high-efficiency and cost-effective device for the conversion of renewable electricity into storable fuels (e.g., hydrogen). Because the poor sintering properties of protonic ceramics, conventional furnace sintering methods for PCECs are usually ineffective, which needs long-term and high-temperature firing. A new one-step rapid laser reactive sintering method was developed for achieving fully densified protonic ceramic electrolyte films [1]. Motived by the discovery of rapid laser processing method , we fabricated PCEC single cells through one-step rapid laser scanning. In this cell, the BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb) was selected as electrolyte materials duo to the high ionic conductivity at relatively low temperatures [2]. (BCZYYb) with NiO cermet materials (40:60 wt%) were selected as fuel electrode. BaCe0.6Zr0.3Y0.1O3-δ (BCZY63) was selected oxygen electrode scaffold for further nanoscale phase catalyst infiltration. The porous fuel electrode layer of cell was prepared by 3D printing from the paste comprised of the mixed powders of NiO and BCZYYb stoichiometric amounts precursor solids (BaCO3, CeO2, ZrO2, Y2O3, and Yb2O3). The electrolyte was spray coated on the fuel electrode surface. The coating slurry was composed of BCZYYb stoichiometric amounts precursor solids, 1 wt% NiO was added in it as sintering aid. Then, the scaffold pastes of BCZY63 stoichiometric amounts precursor solids was spray coated on the top surface of BCZYYb green layer. Laser irradiation on the surface of this green single cells in few seconds. Those precursor solids converted into pure BCZYYb phase (both in fuel electrode and electrolyte layer) and BCZY63 phase (scaffold) by solid-state reactive during the laser scanning processing. The fuel electrode layer and oxygen electrode scaffold layer exhibited expected nanoporous microstructure. The BCZYYb electrolyte layer was fully densified with a thickness of ~20 μm, and bond together with the porous electrodes tightly without crack and curvature. The active oxygen electrode material BaCo0.4Fe0.4Zr0.1Y0.1O3−δ nanoparticles were infiltrated into the porous BCZY63 scaffold and calcinated at moderate temperatures. A protonic ceramic electrochemical cell was manufactured successfully with Ideal sandwich structure. This cell exhibited a moderate electrochemical performance. Keywords: Rapid Laser sintering, Protonic ceramic fuel cell, Solid-state reactive sintering, 3D printing.